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§6553. Gas Compressors and Gas Plant Protection.

(a) When a gas compressor plant discharges gas into a line to which other sources of gas supply are connected, except when discharging into a public utility distributing system, there shall be a valve installed in the plant's discharge line, or lines, for the purpose of preventing the return flow of gas.

(b) Gas compressor discharge lines shall have a pressure relief device. There shall be no intervening valves or fittings between the compressor and its pressure relief device nor between the pressure relief device and its point of discharge, which would render the pressure relief device ineffective.

The pressure relief safety device shall be set to open at a pressure not to exceed one hundred and ten percent (110%) of the maximum allowable working pressure of the cylinder. The relieving capacity of the pressure relief device shall be such as to prevent a rise of pressure in the cylinders of more than ten percent (10%) above their maximum allowable working pressure as established by the manufacturer.

NOTE: A valve locked in the open position does not render the pressure relief device ineffective.

(c) Where a gas compressor pressure relief device discharges into the atmosphere, the discharge outlet shall be located outside of the compressor building; and if it discharges adjacent to the building, the discharge outlet shall be located above the compressor building eaves.

(d) Where hazardous quantities of liquid may be present in the incoming gas to compressors, an inlet scrubber shall be provided and a device installed on it that will either give an audible warning or shut down the compressors if the liquid in the scrubber exceeds a predetermined level.

(e) Gas lines connected to compressor intakes shall be provided with shut-off valves in a safe location outside the compressor building, if there is one, but in no case within a reasonable distance of the compressor.

(f) Before maintenance work requiring the opening of lines or equipment containing gas is performed on a compressor or its suction or discharge piping, the valves in the intake and discharge lines shall be closed and locked to protect employees from the danger of escaping gas. If this is inadequate, the lines shall be blinded, or other equally effective means taken, to prevent the escape of gas.